The Clinical Core is to provide centralized clinical expertise for conducting research in human subjects to facilitate and support the ultimate goals of the Center, which is to optimize mucosal immunity via targeting dendritic cell subsets. This Core will operate according to the highest standards of good clinical practice (GCP). Our studies in human subjects will include: a) healthy normal volunteers who will be immunized with licensed influenza vaccines; and b) individuals with naturally-acquired influenza infection. We have initiated a careful and detailed process for testing and evaluation of the different vaccine candidates developed by the Center using a number of in vitro assays and in vivo models, including both Humouse and the nonhuman primates. It is essential that we analyze side by side the immune responses induced by the most promising vaccine candidates with the immune responses generated after immunization with licensed influenza vaccines and naturally acquired infection. This Clinical Core will take advantage of the established infrastructure and successful collaboration initiated during the previous U19 Center award between the investigators at BUR and the infectious diseases clinical investigators at UT Southwestern Medical Center. Our studies will include three aims: AIM 1. To obtain sequential clinical samples including both nasal wash and blood specimens from a group of healthy adult volunteers immunized with both live attenuated (LAIV) and inactivated influenza (TIV) vaccines. AIM 2. To obtain large numbers of immune cells via cell apheresis to perform detailed analysis of immune responses in a small number of healthy volunteers immunized with' LAIV and TIV. AIM 3. To obtain sequential clinical samples (nasal wash and blood) to assess immune responses in previously healthy adults (age-matched with volunteers) who develop natural influenza infection. By consolidating all proposed clinical studies in one unified structure, the Clinical Core will provide high-quality clinical samples for the different analyses and immune studies proposed across the projects in the Center facilitating the work of the Center investigators,and providing synergy and integration. This infrastructure will optimize the use of samples and resources in an efficient and cost-effective manner.